+%
+% character aligment:
+%
+% The custos is assumed to be vertically centered around (0, 0).
+% The left-most edge of the custos should touch the vertical line
+% that goes though the point (0, 0).
+%
+% set_char_box() conventions:
+%
+% * breapth: Ignored (as far as I know). Should be set to 0.
+%
+% * width: Should cover the horizontal range of the custos that is to
+% be printed in the staff. If the custos has an appendage that is
+% supposed to reach beyond the right end of the staff, the width
+% should be set such that the appendage is outside of the char box.
+%
+% * depth: Should match the bottom edge of the custos. Affects
+% vertical collision handling.
+%
+% * height: Should match the top edge of the custos. Affects vertical
+% collision handling.
+%